The Paradox of Efficiency

The advent of more efficient electric lights ought to be hailed as a great step forward for energy conservation, since lighting consumes a hefty 6.5 percent of the world’s energy supply.

But human behavior regularly confounds expectations, and in this case we find a seeming paradox. Researchers expect energy efficiency increases to raise the amount of energy consumed in lighting. It’s basic economics, in a way.

Surely light is a good thing. And the law of demand in economics suggests that if the price of a good thing goes down, people will always want more of it. (The concept of “enough” has never really caught on in economics.)

This was the case when gas lighting replaced candles and whale fat – cheaper light led to higher demand, including street lights (!). The conversion to more-energy-efficient electric lights led to another increase. A typical resident of the western world now consumes 100,000 times as much light as he would have had he lived in western Europe in 1700. 

Light is so much in demand that the increase in consumption wiped out the gains from efficiency, so more energy rather than less was used. The same is expected to occur in the future, as solid-state lighting replaces today’s compact fluorescent lamps. This was recently reported in Economist news magazine. They’ll be better for the environment, if and only if we were satisfied with today’s level of lighting. But we won’t be, if history is a judge. Efficiency is expected to increase by a factor of 3, while consumption of light is expected to increase by a factor of 10. We’ll need twice as much energy to make that light.

We’ll have brighter indoor lighting, better-lit retail spaces. And, security-obsessed as we are, we’ll light up outdoor spaces that are currently dark. That would be a good thing in some neighborhoods, but it has side-effects.

If you haven’t seen the Milky Way lately, get your views in now. Light pollution (combined with air pollution) already obscures all but the brightest stars in urban areas.

More efficient cars don’t lead to less gasoline consumption, either, in case you were wondering. Cheaper car travel makes private transportation more attractive relative to public transportation. With more efficient cars, people drive more.

It doesn’t mean we shouldn’t pursue those gains, it just means we can’t expect relative prices to make us virtuous people. We still have to confront the culture of “more” in the context of well-lit 24/7 consumerism.

This is known as Jevon’s effect. This is another reason we should embrace a carbon tax if we want to move to a more sustainable future.

Eric Rempel